Researchers have discovered what may be the key to one of the main sources of food poisoning - Salmonella.

They have identified a gene which is responsible for providing the right environment for Salmonella to multiply inside human cells.

The researchers, from Hammersmith Hospital, London, believe the gene could be an important target for the development of new drugs to treat bacterial infections such as TB and typhoid, which is caused by a strain of Salmonella.

Our challenge now is to exploit our findings to develop more effective vaccines

Professor David Holden, Imperial College School of Medicine

When bacteria invade the human body they are engulfed by specialised white blood cells called macrophages and trapped inside a membrane bag, where they are attacked and killed by the cell's chemical defences.

Disease-causing bacteria such as Salmonella survive by modifying these bags in order to avoid these attacks and to multiply.

Professor David Holden, and his team in the Infectious Diseases Department of the Imperial College School of Medicine based at the Hammersmith, have discovered that the camouflage is controlled by a gene called SifA.

They found that Salmonella with an inactivated SifA gene no longer has this ability to multiply, and can be killed off by the macrophages.

Many other infections, such as TB, function in the same way as Salmonella - making the discovery crucial in the long term fight to defeat these global killers.

Professor Holden, said: "This discovery could be significant in controlling serious bacterial infections, such as Salmonella.

"Our challenge now lies in using this gene to understand more about this fundamental aspect of infectious disease, and to exploit our findings to develop more effective vaccines.

"This is especially important since many Salmonella strains are becoming resistant to antibiotics."

The research is published in the European Molecular Biology Organisation (EMBO) Journal.